At present, screens widely used in the market are liquid crystal displays (LCD) and organic light emitting diode displays (OLED). The OLED is mainly used in small-sized panels. As compared with the LCD, the OLED has advantages including light and thin, low power consumption, high contrast, high color gamut, the ability to achieve flexible display, and so on, and thus represents the development trend of next-generation displays. The OLED includes a passive organic light emitting diode (PMOLED) and an active matrix organic light emitting diode (AMOLED), wherein the AMOLED can be implemented by combining a low temperature polysilicon (LTPS) backboard and a fine metal mask (FMM), or combining an oxide backboard, a white organic light emitting diode (WOLED) and a color film. The former is mainly applied in small-sized panels, corresponding to mobile phones and mobile applications, and the latter is mainly applied in large-sized panels, corresponding to the applications such as monitors and televisions. The manner of utilizing a fine metal mask (FMM) is achieved by vapor deposition of an OLED organic material onto the LTPS backboard by means of vapor deposition in accordance with a predetermined procedure, and forming a red-green-blue device using a pattern on the fine metal mask.
During the preparation process of an existing AMOLED, the vapor deposition of an organic material is mostly carried out in a vacuum chamber using a crucible as an evaporation device. The crucible has a grooved structure for loading the organic evaporation material, and heating wires are provided outside the crucible for heating the crucible. The conventional crucible is heated only by the heating wires, and the uniformity of the heating temperature is achieved only by means of the distribution of the heating wires. However, the heating wires are easily deformed, so that easily results in poor temperature uniformity of the crucible, which may cause the problems such as uneven thickness of the vapor-deposited film layer, denaturation of the material inside the crucible, and so on.